The avermectin family, of which invermectin is a member, encompasses a series of very potent antiparasitic agents that are useful against a broad spectrum of endoparasites and ectoparasites in mammals as well as being useful in agriculture against various parasites found in and on crops and in soil. Ivermectin is disclosed in U.S. Pat. No. 4,199,569 issued Apr. 22, 1980 to Chabala and Fisher.
The avermectins possess a disaccharide moiety at the 13-position consisting of the .alpha.-L-oleandrosyl-.alpha.-L-oleandrosyl group. This disaccharide moiety may be removed as described in U.S. Pat. No. 4,206,205 to produce the corresponding aglycone derivatives having an hydroxy group at the 13-position. The 13-hydroxy group may be removed as described in U.S. Pat. Nos. 4,171,314 and 4,173,571 to form the corresponding 13-deoxy compounds.
Another family of compounds, identified as the milbemycin family, that are disclosed in U.S. Pat. No. 3,950,360 has the same 16 membered ring as the avermectin compounds, although they lack the disaccharide moiety and also differ in some substituent groups.
A major goal of research is to provide new, active avermectin and milbemycin compounds.